Female dogs typically come into heat about twice a year, or roughly every six months
. However, this frequency can vary depending on the dog's breed, size, and individual factors:
- Small breed dogs may go into heat up to three times a year
- Giant or large breed dogs may only cycle once a year
- Some breeds like Basenjis, Tibetan Mastiffs, and Dingoes may cycle only once annually
The first heat cycle usually occurs between 6 to 12 months of age, with smaller dogs tending to start earlier (around 6 months) and larger dogs later (up to 18-24 months)
. Each heat cycle lasts about 2 to 4 weeks, with the fertile period (estrus) averaging around 9 to 18 days
. After the first heat, cycles tend to be fairly regular every 6 to 7 months, although the intervals can lengthen as the dog ages
. Spaying a dog stops the heat cycles entirely
. In summary, most female dogs come into heat twice a year, but breed size and individual variation can influence the exact frequency and timing.
